Visual Secret Sharing Using Cryptography

The Visual Cryptography Scheme (VCS) is a kind of secret sharing scheme that focuses on sharing secret images. The basic idea of the visual cryptography scheme is to split a secret image into number of random shares (printed on transparencies) which separately reveals no information about the secret image other than the size of the secret image. The secret image can be reconstructed by stacking the shares. The underlying operation of this scheme is logical OR operation. The Embedded Extended Visual Cryptography Scheme (EEVCS) uses meaningful covering shares. The scheme EEVCS can be implemented by embedding random shares of secret image into meaningful cover images. The halftoning method is used to convert the gray scale image into binary image. After Studying existing Dithering technique of half toning, Otsus Thresholding method is proposed. Least Significant Bit (LSB) matching steganography technique is used to hide the secret pixel information into the covering images. Related works on visual cryptography scheme are also investigated and it was observed that visual quality of recovered secret images are low by using existing dithering halftone based EEVCS techniques. Including Otsus Thresholding method for halftoning of an image can produce bright image in a better way. LSB matching steganography is a useful method to hide the secret image. This research aims at employing LSB matching steganography with Otsu's method to develop an efficient EEVCS system.